Sorry to necrobump but I find this topic endlessly fascinating, there always seems to be two extreme sides in this particular debate, the extreme audiophiles vs the extreme anti-audiophiles. One side swears bi amping your speakers with gold plated cabling produces 'sparkling' treble and 'spacious' realism, while the other screams 'I can't hear the difference on MY equipment between 128 and 320 so it DOESNT EXIST. I think the reality falls somewhere in between. Will a higher quality amp reduce THD and possibly sound better? Certainly, but not on speakers that aren't capable of resolving those details, or in a listening evironment with improperly placed speakers or lots of reflective surfaces, especially if the system hasn't been properly eq'd. The other comment regarding speakers, I went to a trip to the local hifi shop and you can most CERTAINLY hear the differences between expensive speakers. Case in point, I auditioned a pair of Paradigm Monitor 7's (about $700 a pair) and while there the salesman had me also listen to a pair of $3500 Thiele's swearing they were WAY better than the Paradigms. As you may know, Paradigm are a canadian speaker maker who focus on linear sound and don't do any marketing or advertising, preferring to spend those dollars on r and d. Thiele is one of those 'boutique' brands that are darlings of the 'audiophile' industry. Needless to say, the Paradigms presented a wonderfully crisp, clean and open sound, ie you could close your eyes and they melted away with a soundstage that extended in front and behind them, and an open 'un veiled' treble. The $3500 Thiele's on the other hand, the soundstage collapsed into a flat, dull lifeless sound. Even my wife, who probably doesn't know the difference between a woofer and a tweeter could easily tell the difference. In reference to 'can you hear the difference between 320 and 128', on some samples, absolutely not. However having my iems properly eq'd to reduce their nasty peak at 5khz, I have some music where a certain percussion instrument completely dissappears anywhere from lame -v6 on up to -v2. In fact I have to encode it at -v0 before the percussion is properly heard and sounds just like the FLAC. On my acer aspire netbook, I can't even hear that sound with the FLAC file. So, in the end, not all audiophiles are nuts, but a good portion of them are. I'm actually gonna do a post with some samples for others to test, because like I said, I can't even hear that detail on my netbook, while it's plainly audible on my sansa clip and phone at lame -v0 but not lame -v2. Could be another 'killer sample'.

Thank-you, greynol. I think to clarify my original post, what I meant to imply is that on one side of things, you have those audiophile publications that drone on about the benefits of bi wiring, 24 kt gold cables, and 96khz sampling. On the other you have those obsessed with spectrum analysis graphs (those who mess with LAME's lowpass), THD tables (nobody can hear the difference between 0.05 and 0.5%), etc, etc.

The 'middle' that I implied are those that use sane methods of testing, and human ears.

Yes, I've heard a few people put forth that claim, and it's kind of fun to ask them for the listening tests results that prove their claim, frankly.

A proper DBT of the right structure for the signals at hand is the thing to rely on.

Hm, well. DBTs are well suited to verify that there is some kind of audible difference (if there is such one). Less well suited to falsify differences. But I guess the OP has a good point in those cases where are differences that the ears can tell. Then the DBT procedure does not offer enough tools to tell which one is closer to truth (lack of reference), nor to describe what the differences are (lack of vocabulary). Measurements like THD are 'objective', but they do not objectively measure quality. (Rather, like you indicate, it is not that far from objective to claim that THD doesn't.)

Hm, well. DBTs are well suited to verify that there is some kind of audible difference (if there is such one). Less well suited to falsify differences.

If by "falisfy differenences" you mean prove that a difference does not exist, are DBTs any worse than anything else given that proving negative hypothesis is difficult or impossible?

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But I guess the OP has a good point in those cases where are differences that the ears can tell. Then the DBT procedure does not offer enough tools to tell which one is closer to truth (lack of reference), nor to describe what the differences are (lack of vocabulary).

Which DBT procedure are you speaking of? It's a given that ABX is not very good all by itself for characterizing differences that are known to exist. OTOH, other means exist for that and seem to be generally recognized.

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Measurements like THD are 'objective', but they do not objectively measure quality. (Rather, like you indicate, it is not that far from objective to claim that THD doesn't.)

THD is an abstract quantity. It is just a means for characterizing nonlinear distortion, and one that has obvious and well-known flaws. Other means are commonly used for this purpose and they have their own strengths and weaknesses. THD is perhaps most useful when it is known to be exceeding low, which is now common.